The present disclosure generally relates a display device and, more particularly, to the three dimensional display device and the control device thereof.
Traditional three dimensional image frame signals are displayed on the cathode ray tube (CRT) display devices. The image frame signals for the left eye and the right eye (referred to as left-eye frames and right-eye frames hereinafter for conciseness) are alternately raster-scanned on the CRT display device and the left-eye lens and the right-eye lens of the shutter glasses become non-opaque (e.g., transparent or translucent) correspondingly. By properly configuring the left-eye lens and the right-eye lens of the shutter glasses, the left eye and the right eye of the viewer may only perceive the left-eye frames and the right-eye frames, respectively. The left-eye frames and the right-eye frames are combined in the brain of the viewer and provide the perception of three dimensional depth of the image frames. The term “image” referred in the present disclosure may comprise still pictures, motion pictures, video, or any suitable type of visual expression.
In some display devices, however, the picture elements (pixels) keep displaying the same image data until the pixels are refreshed, e.g., the liquid crystal display (LCD) devices, the liquid crystal projection devices, the organic light emitting diode (OLED) display devices. Therefore, the image data of the right-eye frame displayed on the pixels of the display device are sequentially refreshed into the image data of the left-eye frame when the left-eye lens is non-opaque and the image data of the left-eye frame are sequentially refreshed into the image data of the right-eye frame when the right-eye lens is non-opaque if the traditional lens control mechanism is adopted with these types of display device. The left eye and the right eye of the viewer both perceive image frames mixed with part of a left-eye frame and part of a right-eye frame. The viewer perceives the ghost imaging when watching the three dimensional images on these types of display device and the viewing quality is severely influenced. Therefore, when three dimensional image frame signals are displayed on these types of display devices, the traditional lens control mechanism for the CRT display devices is no longer applicable.
Some approaches try to solve this problem by configuring the lenses of the shutter glasses to be non-opaque only in the vertical blanking interval (VBI). The VBI is the period of time after the image data of one image frame have been refreshed and before the image data of the next image frame start to be refreshed on the display device. Thus, the pixels of the display device are completely refreshed and display only the left-eye frame or the right-eye frame in the VBI. The viewer does not perceive an image frame mixed with part of a left-eye frame and part of a right-eye frame in the VBI.
The VBI is only a short period of time and the brightness of the image frames is not enough if the viewer may only perceive the image frames in the VBI. Some conventional approaches, e.g., the disclosure in U.S. Publication No. 2007/0229395 A1, extend the duration of the VBI to enhance the brightness of the image frames perceived by the viewer. The extended VBI approach, however, is not compatible with current standards and brings the compatibility issues. The display control device and the display device need to be re-designed and realized with special designed components to support the extend VBI approach. The design complexity and the production cost are therefore increased.